BP845 bandpass filters are designed to provide excellent transmission at 850nm while blocking visible and lower near-IR wavelength transmission. At the same time, it will block longer wavelength near-IR light – particularly at 940nm. In covert or other near-IR applications where more than one near-IR light source is desired (typically 850nm and 940nm would be two common choices), BP845 can be used with cameras and lighting designed to capture 850nm images and will block unwanted/interfering 940nm illumination.